The Kardashian sisters are well known for their fights, dramas and all-round support – but Kourtney may not see the funny side after Khloe posted footage of her on the toilet to celebrate her birthday.

The eldest of the Kardashian offspring turned 38 yesterday, and to mark the occasion, Kourtney made her a video and put it up on Instagram.

It started off with clips of Kourt looking beautiful and well-presented – then descended into footage of her looking so drunk she could hardly stand.

Khloe's video montage of Kourtney started so well (Image: Instagram)

It showed them drinking rum and smoking cigars in Havana (Image: Instagram)

Kourt riding with momager Kris Jenner (Image: Instagram)

Wearing a black leather sheath dress and over-the-knee black boots, and with her hair in one long braid, Kourtney shouts into the camera at what looks like a house party.

But in the next clip she can be seen perching on the loo trying to cover herself with her hands when Khloe follows her into the bathroom.

"Kourtney, are you a celebrity?" Khloe questions her when Kourt has had a few more drinks.

The two sisters do a dance routine (Image: Instagram)

Kourt can be seen drunkenly holding onto something at a house party (Image: Instagram)

Khloe even showed Kourtney on the toilet (Image: Instagram)

"I'm a celebrity, get me out of here!" Kourtney slurs back.

"And what happens if I don't, b***h?" Khloe asks.

"I'll f**king b***h you the f**k up, you f**king– " the birthday girl shouts as the film cuts off.

Kourtney hasn't yet acknowledged the birthday offering publicly, but presumably she's not too embarrassed to have had her most intimate moments published to the world given that she shared a naked picture of herself with her own followers.

Mum-of-three Kourtney is clearly proud of her body

The mum of three captioned her nude photo "birthday suit", prompting praise and amazement from her 56 million followers.